This invention relates to a method for manufacturing a resin-reinforced carbon fiber bar product and more particularly, to a method for manufacturing a resin-reinforced carbon fiber bar product which is suitably employed as the material for a fishing rod or alternatively as an antenna pole or a mechanical support for supporting light weight mechanical parts.
Since it has been known that carbon fiber is quite tough and light weight, many attempts have been made for the purpose to obtain a tough plastic bar product employing carbon fibers, but unfortunately, such prior attempts have ended in failure. Although carbon fiber has properties similar to those of glass fiber, the method found suitable for the manufacture of a glass fiber bar product has encountered difficulty in the application to the manufacture of a carbon fiber bar product. The reason is that for the manufacture of glass fiber bar products, although polyester or epoxy resins are generally employed as the materials for reinforcing glass fiber bar products, but for the purpose, only such resins which can be rendered to a liquid state having a high fluidity at room temperature (15.degree.-35.degree. C.) and set at room temperature or at lower temperatures. When such resins are employed together with carbon fibers in the manufacture of a bar product, the resins have the following disadvantages, that is, the resins encounter difficulty in uniform distribution of the resins in carbon fibers and when a bar product is manufactured by manually impregnating the carbon fibers with the resins by the polyester resin-reinforced carbon fiber bar production method, the obtained resin-reinforced carbon fabric bar product is very low in strength. This low strength of the obtained carbon fabric bar product is considered due to the inherent properties of the carbon fibers themselves. Therefore, as resins useful in the manufacture of a resin-reinforced carbon bar product, only epoxy resins having high viscosity and high thermal melting and setting properties can be employed. Such epoxy resins are similar to phenol resins in properties and when such epoxy resins are contained in carbon fibers, methyl ethyl ketone is employed as the solvent for such resins and when phenol resins are contained in the carbon fibers, methyl alcohol is employed as the solvent for such resins. After the impregnation of the carbon fibers with the resins, it is necessary that the solvent employed is evaporated and then the resin-impregnated carbon fibers are shaped. The epoxy or phenol resin-impregnated carbon fibers have a higher viscosity than that of the fluidal epoxy resin-impregnated carbon fibers.
As one example of the products formed of resin-impregnated carbon fibers, there is a hollow glass-phenol fishing rod material is known. In the manufacture of such fishing rod material, it is necessary that glass fibers are compressed by a roll which imparts high compression pressure to the glass fibers to a bar-like intermediate product, a tape of cellophane is tightly wound about the intermediate bar-like product and the tape wound intermediate bar product is set by applying heat thereto. However, since the hollow fishing rod has no iron core therein, the hollow fishing rod may be easily drformed or damaged while the rod is being rolled. In addition, the cellophane tape can not be wound about the compressed glass fibers with a sufficiently high tightness. And in the manufacture of a polyester fishing rod, the polyester-impregnated carbon fibers are attempted to be formed into a bar-like intermediate product by drawing the carbon fibers through a pipe-shaped mould, but since the resin can not flow between the fibers, the drawing of the fibers through the pipe-shaped mould encounter difficulty because the resin has a high viscosity. And the resin-impregnated carbon fibers require heating thereof at a high temperature (150.degree. -180.degree. C.) for a long time (1-2 hours). Thus, the manufacture of the hollow glass-phenol fishing rod and polyester-impregnated fishing rod has encountered difficulty.